Signaling apparatus



Feb. 14, 1923.

L. S; THEREMIN SIGNALING APPARATUS Filed Dec. 5. 1925 5 Sheets-Sheet 1Fig.1.

III III! Feb. 14, 1928.

L. S. THEREMIN SIGNALING APPARATUS Filed Dec. 5, 1925 5 Sheets-Sheet 2Fig. 13.

' W s I 277 J22 vlziorz We Y W a Feb. 14, 1928.

- 1,658,953 L. S. THEREMIN SIGNALING APPARATUS Filed Dec. 5, 1925 5Sheets-Sheet 3 ff I Feb. 14, 1928.

L. s. THEREMIN SIGNALING APPARATUS Filed Dec. 5. 1925 5 Sheets-Sheet 5J72 verzior:

By Mafia/ac,

Patented F elm l4, 1928.

" UNITED STATES PA'rsNr OFFICE.

LEO SSERGEJEWITSCH THEREMIN, OF LENINGRAD, RUSSIA, ASSIGTTOR TQ FIRM M.J. GOLDBERG AND SOHNE G. M. B. 31., OF IBEBLIN-CH ARLOTTEN'BURG, GER-MANY.

SIGNALING APPARATUS.

' a Application filed December 5,-1925, Serial No. 73,530, and inGermany December 11, 1824.

This invention relates to signaling and alarm devices and aims toprovide a novel method of and means for generating sound on producingvisual signals for alarm purposes. It embodies an electro-magneticsystern of high-frequency oscillation potential operable by the approachthereto of an object such for example as a person entering a roo whenthe apparatus is applied in a burglar 310 alarm system, a trainapproaching a signal block when applied in a railroad signaling system,etc. An apparatus embodying the invention may also be controlled byother factors, such as an increase of temperature when adapted in a firealarm system, or by some other factor when appropriately applied tooperate upon the happening of an anticipated disturbance'or event.

In other words, movement of an object or other variable factor inpredeterminable relation to an, apparatus embodying the invention causesa variation in the self-inductance or capacity of the oscillating systemthereof, which in turn brings abou'ta vari system and such frequencyvariation causes operation of the sound means. 1

An object of the invention is to provide an apparatus of the specifiedtype, the operation of which will not be affect-ed by the variables towhich related apparatus have generally been subject and to this end isde signed to respond not to variations of fre-' quencybut to an abnormalrate of such variation, and to operate only when such rate exceeds orfails to attain a certain value, as opposed to the normal rates ofvariation caused byc'ertain conditions hereinafter described. k

Apparatus of the general type to.which this invention relates haveheretofore been operated by frequency variations and not by the rate atwhich such variations occur.- Such apparatus has been objectionablebecause it will .not operate properly without continual supervision andregulation. This fact is due to the influence of several factors whichbecome so great in a comparatively short time as to interfere with theoperation of-the apparatus.

i The defective conditions ation in the frequency of oscillation of the:

produceror signaling 1n such apparatus are either inherent therein andresult from factors which influence the oscillations of the.electro-ionic oscillator preferably em-,

ployed, such for example as the heating, the plate potential, thevacuum, the electron emission',-etc., or are due to extraneous causes,such as atmospheric influences, temperature, the varying percentage ofmoisture in the walls or structures alon or in which the wires of thesystem are disposed, or to other similar causes. The influence of thesevariables is so great that. it cannot be compensated by the meansordinarily provided.

On the other hand, in an apparatus embodying this invention, theinfluence of such factors is eliminated by making the apparatusresponsive to the rate of variation of the frequency, rather than to thevariation of frequency. The influence of the aforementionccl variablefactors is compensated by an appliance which may be termed a regulatorwhich is operated at a certain speed, and the apparatus will respondonly if the rate of variation of the frequency due to the ap,

proach of an objector other controlling factor is abnormal and exceedsthat speed,

By such means, the apparatus is rendered independent of the variationsof frequency which are due to said variable factors, does not requirecontinual supervision and regulation, and will operate in areliable andsatisfactory'manner.

he apparatus may be so designed as to respond under any desiredconditions, for

instance, if applied toa building in a burglar-alarm system, it may bemade to respond and signal an alarm as a burglar creeps within distanceto influence the system even before entering the premises, because hisbody, upon approaching in proximity to the system,,will cause vibrationsto be set up therein at a rate of frequency variation far greater thanthe rate of variation due to said variable factor. Similarly, if appliedin a fire-alarm system, the apparatus may be made to respond only toabnormal -variations or sudden rise of temperature in the room whereinit is arranged, even if the actual temperature inbrease' is relativelysmall;

The regulator, which may be designed for any speed and-magnitude ofcompensatlng action,- will gradually and automatically vary itsself-inductance or capacity and con sequently the characteristics of theoscillating circuit in such a manner as to obtain the desired result.

In the drawings, several forms of apparatus embodying the invention andoperable according .to the method embodying the same are illustrateddiagrammatically by waIy of example. I

. 11 said drawings,

- Fig. 1 is a diagram illustrating'the underlying principle of theinvention; 3

Fig. 2 is a diagram ofa regulator;

Figs. 3 to 7 illustrate various heat-operated regulators;

Fig. 8 is a diagram of an arrangement wherein regulators according toFig. 9 are employed;

Fig. 9 illustrates a mechanically operated regulator; x

Fig. 10 illustrates a modification of the regulator shown in Fig. 9;

.Figs. 11 to 15 illustrate various fire-alarm systems embodying theinvention; and

Fig. 16 illustrates a complete installation comprising a-- central andthree local protection stations.

In Figs. 1, 2-and 16, E represents a highvoltage battery.

For the purpose of disclosing the nature of the invention, Fig. 1 showsa system of connections in which variations of the natural period of anoscillating system 235 are caused by the variation of the capacity of anantenna. or control conductor connected to it. The antenna comprises awire or flexible lead whioh'is supportingly extended along, around orwithin the area or district 40 to be protected. Said antenna has adefinite normal capacity and this capacity is affected when a personsuch as a burglar or any object approaches it. The antenna isaccordingly hereafter referred to as a control conductor and obviouslymay take various forms and be arranged in various ways dea pending uponthe use that is made of the -An electro-lonic oscillator or generatortube 237 isin-ductively coupled to the oscillating circuit 235. Thefrequency of the oscillator 237 is adjusted to about the reso- .nancepoint of the oscillating circuit 235 by proportioning the constants ofthe asso- 5 .ciated oscillating circuit 236. .When the capacity of theantennas or control conductor isvaried-by the approach of aforeignobject,

a corresponding variation of the amplitude of the oscillations of theoscillator 237 takes place resulting from and depending upon thedifierence between the periods of the oscillating systems 235 and 236.

The variation of the grid'current in a grid-leak resistance .234 causesa variation of the potential on the grid of a second. tube 1 signalingapparatus.

'tion and v A s 238, and the plate current of the tube 238, which Variesaccordingly, may be measured by the measuring instrument 239: Iftheoscillating systems 235 and 236 are so tuned i that a retardation ofthe natural'frequency of the circuit 235 brings about a reduction of theoscillation energy of the tube 237 an increase of the capacity of theantenna causes an increase of the plate current through the "measuringinstrument 239, the increase being substantially proportional to theincrease in' capacity. As long as the object to be detected is outsideof theoperating range of the antenna, no variation in the deflection ofthe instrument 239 will take place. The plate current increasesgradually in proportion to the rate at which the obgect approaches theantenna, until it 4 reaches its maximum value when the object hasreached the antenna When the foreignbody or object moves'slowly towardsthe antenna, the increase of the plate current of the tube 238proportionally takes place slowly and gradually. When. the movementoccurs at a higher speed, the plate current rises at a correspondingly.greater rate.

Fig. 2 is a diagrammatical representation of the connections of theregulators; i. e.,

the devices which compensate for the normal plate current variations.,The amplifier tubes 111 and 112, which correspond to the tube 238 inFig. 1, are connected .to'a I heating winding. 113 instead of ameasuring instrument 239. Said winding 113 isshown. disposed around anexpansible metal core connected to a condenser 114. Said metal emanatingfrom the heating winding 113 core expands under the action of the heatto move the plates of the condenser closer vtogether, whereby thecapacity of the condenser is increased. If the condenser 11 i isappropriately connected in the circuit'of the oscillator tube 237, itwill vary the capacityofithe oscillator circuit in such a manner as tocompensate for the variation which has occurred in the antenna systemif. this tion dueto the rapid approach of a foreign body towards theantenna, while if the capacity variationis sufliciently slow, theregulator is able to compensate for the varia prevent the production ofa warning signal. 1

. Before giving a detailed description of a I complete installation, theconstruction of varlous forms of regulators, will first be describedwith reference to Figs. 3 to 7 of the drawings.

In these regulators, the con-- trolling current causes a slow. variationof .is supported on the larger portion of a twodiameter glass tube-135,136 containing mercury. A thin metallic cylinder 137 is shownsurrounding the larger portion 135 of the tube, while a layer of mica138 surroundssaid cylinder. The coil 139 is disposed on the mlcalayerand 'is in turn surrounded by'heat-insulation 140. The coil 139correatures.

sponds to the coil 113 of 2, and is connected in circuit throughconductors 141. The narrow portion 136 ,of the tube is surrounded by aglass tube 142 which is substantially filled with mercury. \Vhere thetube 142 rests on the larger portion 135 20 of the first tube, aninsulator 143 is inserted between the tube portions 136 and 142 so thatthe mercury'in the member 135 will not influence that within the tube142. An extension 144 is provided at the upper end of the tube 136 toprevent bursting in case of overheating. A conductor 145 is connectedwith the metallic cylinder 137, and a second conductor 146 is connectedto the mercury in the tube 142.

When current fiows through the heating coil 139, the mercury in theportion 135 expands and rises in-the narrow tube 136. The mercury in themember 135 and the metal cylinder 137 constitute thelayers of conductingelements of a fixed condenser which is connected in series with avariable condenser, one element of which is the mercury column in thetube 136, and anotherdis the mercury column in the tube 142. Thecapacity of the. variable condenser varies with the level of the mercuryin the tube 136. This form of regulator comprises a combination of afixed and a variable. condenser which are connected in series, and thecapacity of I the variable condenser is varied. in substantially 'the'same manner as that of the condenser 114 of Fig. It will be, apparentthat this regulator is particularly suitable for temperaturesconsiderably greater than ambient temper- Fig. 4 illustratesanother formof regulating device wherein a heating coil 148. within a glass vessel149 filled with xylol -or another-liquid having a high ten'iperatureco-eflicient of expansion, is adapted to be (onnected in circuit bymeans of the con ductors 147. A tube 150 connects the upper end of thevessel with a globe 151, the upper and greater portion ofwhich isoccupied by the xylol or othe'r'li'quid, .while its lower portioncontains mercury supplied through a tube 152 connecting said globe 151with a second globe 153, the latter having an upwardly extended tubeprovidedwith an connected with the conductors 147 enlarged portion 155at its top. Said glass tub e 154 is coated with a metal layer 156 whichis connected with a conductor 157. A

conductor 158 is connected with the body of mercury in the tube 152.

According to the last described construction, when current flows throughthe heating coil 148, the xylol or other fluid expands and forces themercury up ,in the tube 154, so that the capacity of the condenserformed by the mercury column in the tube 154 and the metal layer 156' isvaried.

Preferably, the vessel 149 is arranged in a casing 160 filled withheat-insulating material 159. The rate of the capacity variation may bedetermined by varying the heating conditions and the'heat insulation.The space above the mercury in the extention 155 is evacuated or filledwith inert gas. 1

To short-circuit the heating coil 148 in case of excessive heating, twoplates 161 may be arranged in the extension 155 and by conductors 162. v

To provide the desired capacity, said device requires heating totemperatures in excess of the normal temperaturesof the room in whichthe device is placed, i. e., in this device, like that of Fig. 3,temperatures considerably greater than ambient temperatures arepreferably employed.

Fig. 5 shows. a form of regulating device operated bythe thermalexpansion of a solid Heat insulating material 167 is employed aroundtheoutside of the coil 164. A block 168 of fibre or the like, is securedto the top of the rod 165 and a condenser plate 169 is secured to saidblock. Said plate 169 011- poses another plate 170 carried by a fibresupporting plate 171 which is suspended by springs 172 from a metalframe or container 173. Said frame or container which is rectangular incross-section, supports the core 165 on its lower portion and is notthermally insulated. Thumb-nuts 174 are provided for adjusting andcentering the condenser plate 170. When the core 165 expands, thedistance between the condenser plates is reduced and the capacity of thecondenser is increased. i

As the core 165 is thermally insulated while the frame or container 17 3is not, the

temperature difference between said frame the advantage thatthe effectof fluctuations in the ambient air temperatures. is eliminated. r I i kI duplex armature lever 201.

' flows through the coil.

For installations where temperature fluctuations may be disregarded, theregulator may be modified as shown in Fig. 6, wherein are conductorssupply ng current to "a.

" heating coil 176 surrounded by insulating material 177. An expansiblecore 178 for the heating coil carries an insulated condenser plate 180adapted to co-operate with a fixed condenser plate 181 secured to a base15 plate 179 to which the opposite end ofthe core 178 is also secured. Avariable self-inductance may be used insteadof a condenser and such adevice is shown in Fig. 7. The conductors 182-supply current to aheating coil 183 disposed on a core 185 from which it is insulated by alayer 184 of mica. Thermal insulating material 186 is provided for thecoil' 183. A

ring 187 is secured to the upper end of the core and co-operates with aninductance coil 188 on acore 189 shown co-axial with.

the core 185. The core 189 is supported on a frame or container 190carrying binding posts 191 connectedto theends of the in- 30 ductancecoil 188. When the core 185 expands, the distance of the ring187 fromthe coil 188 is reduced, thereby varying the inductance of the latter..

A mechanical regulating device is illus- 35 trated diagrammatically inFig. 8. This view is a continuation or modification of that shown inFig. 1, and the tube 192 of an amplifier corresponds to the tube 238 ofFig.

1, or to the tubes 111, 112 of Fig. 2. In 40 this instance, the tube 192is the last stage of an amplifier system. A magnet coil 193 is connectedwith thetube 192, andreplaces the measuring instrument 2.39 of Fig. 1 orthe heating coil 113 of Fig. 2. The armature 194 is controlled by saidcoil and by a return spring 195 secured to the former. When full currenttraverses the coil 193, said armature isattracted and connects a magnetcoil 196 to a battery 200 by making the contact at 197, while if a Weakor no current traverses the coil 193, the spring 195 will move the sameto close a circuit through the contact 198 and connect the battery to amagnet coil 199. 1 The coils'196 and 199 control a For intermediatevalues of current, the attraction of vthe coil 193 and the force of thespring 195 are balanced and both contacts 197 and 198 are open.

Fig. 9 illustrates f our signaling stations embodying the device shownin Fig. 8. Four sets of magnet coils 196 and 199 are provided, each setacting on an armature 201 fulcrumed at 221 and con- 5 nected withvertical shafts 203. A shaft 208 a regulating device for .is shownadapted to rotate in synchronism with a' distributor which will bedescribed hereinafter. -A friction wheel 204-is secured on the lower endof each shaft 203' adapted to co-operate with friction plates 209 and210 'on the shaft 208. The end portion 205 of each shaft 203 is normallydisposed between a pair ofribs 206 and 207 on said shaft having opposedgaps 219 and 220. While the said end portions of the shafts 203 hebetween the ribs206 and 207, the armatures v '201 are rendered incapableof tilting said shafts by means of brackets 202, and the friction wheels204 will the plates 209 and 210. However, when said ends lieintermediate the opposed gaps 219, 220 of said ribs, the magnet coils196 or 199, as the case may be, are operative to tilt their armatures201 one way or the other, causing the wheels 204 toengage one of theplates be understood that the plates '214 will recede' from, or movetoward the plates 215 depend-.

ing upon which of the plates 209 and 210 the wheels 204 are moved intofrictional contact.

The opposed gaps or aligned openings 219, I

220 in the guide members or ribs 206 and 207 readily permit thelower'ends of the shafts 203 to movetowai'ds the outside of the latterand bring the wheels 204 in frictional contact with one or the other ofthe discs 209 and 210 to impart rotation to the. shafts 212 of thecondensers in the manner rotated syndescribed. The shaft 208 is.chronou'sly with the distributor 308 of Fig.

16 as'will be described hereinafter.

In this way the condenser plate 214 is made to approach the stationarycondenser plate 215 when the shaft 208 is rotated in one direction and,to recede therefrom when the shaft is rotated I opposite direction. Thegaps or ope'nin'gs'219 and 220 in the guides or ribs 206 and 207 permitthe shaft 203 to swing .from'oneoperative position 'to the other whenthe distributor lever 308 of. Fig; 16 makes a complete reyolution,during which'the extended gaudef'end 205 of the lever 203 will lieintermediate said gaps only when said lever arrives. at the beginning ofthe contact period for the associated regulating device of the system.Swinging movement of the lever 203 is-thenljcontrolled by thecorresponding magnet 199 or 196, and the friction wheel 204 thereonisheld friction-.

ally against the. disc 209 or 210 for a 'combe held away from pleterevolution of the shaft 208 and said lever 308.

In this way the capacity of the condenser is automatically increased,reduced or kept constant according to the intensity of the plate currentof the tube 192 of Fig. 8.

In Fig. 10, the condenser plates are slightly modified, the fixed plate222 (corresponding with the plate 215 of Fig. 9) being a hollowcylinder, and the movable cylinder 223 (corresponding with the movableplate 214 of Fig. 9) being disposed inside the member 222. This form ofcondenser may be used in connection with the regulator shown in Fig. 9.

In conjunction with the above described apparatus, automatic fire-alarmdevices may be employed, the same being directly connected with thecontrol conductor. These fire-alarm devices are based particularly uponthe speed of temperature rise caused by a fire. If the temperatureincrease occurs slowly, as in the normal increase of temperature in aroom due to ordinary causes, no signal will be given in consequence ofthe operation of the frequency regulator hereinbefore described. On theother hand, a signal will be given in thecase of a rapid temperaturerise, even if it is relatively small. The apparatus is thus based uponthe utilization of the variations of the condenser capacities under theaction of heat.

Fig. 11 shows a simple device, which, ho wever, becomes operative onlyat sufliciently high temperature. In this case the antenna consists oftwo conductors 264 and 265 connected by easily fusible metal 266. Themetal will fuse when the temperature rises sufliciently, so that the twoparts of the antenna 264 and 265ywill then be disconnected.

Fig. 12 shows a similar device in which overlapping ends of parts of theantenna 267 and 268 are separated by an easily fusible dielectric 269.hen said dielectric fuses upon sufficient temperature rise, an increasein the capacity of theantenna will occur owing to the resultant contactof its ends, the parts thereof thus forming, in effect a condenser, ordirect contact may be made after the material 269 fuses. The deviceshown is simple and operates only at temperatures above a predeterminedvalue.

- In the embodiment illustrated by Fig. 13, the condenser comprisesopposed plates 270 and 27 2 separated byair, the plate 270 being fixedupon a'baseplate 271 and the plate 272 being secured to the strips 274and 275 at which the capacity of the condenser formed by the plates 270and 272 will be varied when perature. If the temperature rises slowly,

a compensation is effected by a regulating device hereinbeforedescribed, and the signaling apparatus will not then be operated.

Fig. 14 illustrates a thermometer device for giving a signal in case offire or the like. In this case, a glass tube 27 9 connects with theglass vessel 278 containing mercury and provided with a metal shell orcoating 282. The tube 279 is encompassed by another tube 280 of greaterdiameter which likewise con tains mercury and is provided with an outermetal shell or coating 281. In the lower portion of the tube 280 isplaced an insulating substance 283. A conductor 284 is connected to theshell coating 282 and a conductor 285 is connected to the mercury in thetube 280, The conductors 284 and 285 may be parts of the antennae of aninstallation embodying the invention. The device operates insubstantially the same manner as described with reference to Fig. 3, theonly difference being that the heating coil is omitted, the heating inthis instance being effected by the ambient temperature.

A modification of the above described device is illustrated in ,Fig. 15.In this instance a glass tube 286 is shown containing a small amount ofa slightly volatile electrolyte 287, the space 288 thereabove beingoccupied by air. A tube 289 extends downwardly through a stopper in theneck of the bulb with its lower end immersed in the electrolyte. IA partof said tube exteriorly of the bulbis encompassed by a metal coating 290to which is connected a conductor 291 which may be part of the antennaof an alarm installation. The outer end of the tube is bent downwardlyas indicated. The bottom of the glass bulb is provided with a metalliccup-shield or coating 292 to which is connected a conductor 293. Whenthe air within the enclosed space 288 is expanded under heat, theelectrolyte 287 will be forced to rise in the tube 289 and bring about avariation of capacity between the condenser elements 290 and 292. Thesensitiveness of this device may be varied by {inclining the tube 289 atdifferent degrees to\a horizontal plane, because the electrolyte to beraised by the same degree of heat will ascend the tube more easily ifthe latter is inclined.

It will be readily appreciated that various other devices for eflectingfire-alarms" may be connected. with the described signaling apparatuswithout departing from the scope of the invention.

Fig. 16 diagrammatically illustrates a complete system having threelocal stations of differing periods. In this illustration,

the three local stations are represented in connection with --a singlecentral station,

The three local stations comprise antennae or control'conductors 300,301 and 302 respectively with coupling coils 303, 304, 305 associatedtherewith. Said coupling coils are shown connected together in seriesand with the couplingcoil .306 of the central erence to the signalingsystems. Said distributor comprises three series of contact strips overor in relation to which a continuously rotating contact-arm 308 ismoved. The intermediate strip' 309'is unbroken, but the inner and outercontact strips are subdivided into three sectors 318, 319, 320 and 321,322, 323 res ectively, corresponding with the number 0 local stations.

The plate of the oscillator tube 294 is I connected with three parallelcircuits comprising a condenser 312, 313, 314, a noninductive resistance315, 316,317 and a variable condenser 329, 330, 331 respectively.

Each resistance is connected to one of the three outer sectors 321, 322,323 of the distributor. The inner sectors 318, 319,- 320 are connectedto a contact 327 through heating coils 324, 325,326, respectively, ofthe variable condensers 329, 330, 331. These condensers are of the formshown in Figs; 3 to 7. However, said condensers may be con 'structed tooperate mechanically as shown in'Figs. 8, 9 and 10.

The rotating arm 308 connects the condensers 312, 313, 314, the,resistances 315,

316,- 317 and the-varible condensers 329,

330 331 successively. in parallel with the sel -inductanoes 296,297. Thevariable con densers 329,- 330,331 have such value as to 've resonancewith the respective antennae.

otation of the distributor alternately tunes the central stationoscillator to waves corresponding approximately to the waves of thelocal stations 300, 301, 302, and if resonance is establishedfthe energyof the oscillator is "transmitted to the antennae. This alters thecurrent in the grid circuit of the tube 294 and causes a -variation-ofthe grid potential and of a grid-leak resistance 332;- Such variation ofpotential is amplified by the amplifier system 333, the current of theamplifier system flowing through the winding of the electromagneticrelay 334. As

theintensity of the amplifier current decreases, the variation of gridotential 1ncreases that is, the greater and the oscillator. I

The relay 334 attracts an armature 335 and said armature alternatelycloses one of the contacts 338, 339 between which is connected anon-inductive resistance 340. A battery 341 and a second electromagneticrelay 342 are in'the circuit formed by the ecomes the difference inperiodicity between the antennae 1 to which a return spring 336 isattached,

portion 337 of the armature and the two contacts 338, 339. The latterrelay attracts an armature 343, the portion 344 of which is connectedwith a return spring 345. The

port-ion 344 ofthearinature 343 may engage 4 one of the contacts 327 and328, A con ductor 346 connects the armature 343 to the heating currentsource 310 of the oscillator and amplifier cathodes. A non-inductiveresistance 347 is connected between the 1 source 310 and the contact328. A relay 348' and an alarm 349 are also connected between oneterminal of the source 310 and the contact 328 inparallel withthe-resistance 347 the resistance serving to diminish the effect of theclosing of the. contact 328 upon the voltage of the source 310. andthereby upon the otherfdevices connected to said source.

When the relay 348 is energized, the armature 350 thereof closes thecircuit of the alarm 352 through the contact 35l.

When a person or foreignobject approaches one of the antennae, the wavelength When a circuit isclosed through the cons tact 339, the relay 342will be traversed by maximum current. The relay 342 will be lde-energized when the circuit is open and,

will be traversed by currentw'eakened' by the'resistance 340 when thecircuit is closed through the contact 338. The armature of the rel-ay342 will assume corresponding attracted, retracted or intermediatepositions, In the attracted position, the contact 328 is closed and the.relay 348 and the two ala1'ms349 and 352 become operative. 'In

,the retracted position, the relay 348 is not energized and contact 327is closed. In the intermediate position, the current through the relay342 is balancedby Y the spring 345,

and no contactlis made bytheai'mature.

In this latter case, the tuning-between the antenna and the oscillator294 is such that onlya smallcurrent flows. through the relay .334.When,the current increases, the arma- "ture 335 assumes an intermediateposition and the armature 343 of .the relay 342 closes a circuit throughthe contact 327. In consequence, the heating coils 324, 325 326 arealternately heated'by alternating Current from the source 310. Thisvaries the regulator capacities as described abovev in connection withFigs. 3-7, and the tuning between the antenna and the oscillator 294340, thereby opening the circuits of the heating coil-s 324, 325 and 326at the contact 327.

In this manner, the normal fluctuations of antenna capacity arecompensated to prevent the undesired operation of the alarm. Thecompensation for each antenna is effected independently by means of thedistributor 30,7.

In case of sufficiently high resonance between an antenna and'thecentral station-oscillator, for instance in consequence of the approachof a body towards the antenna, the plate current of the amplifier 333flowing through the relay 334 increases and the relay closes the circuitof relay 342 through the contact 339, whereupon the relay 342 energizesthe alarms 349 and 352. The alarm 349 stops ringing when the regulatorhas detuned'the circuits as described above. However, the alarin352remains in operation until the armature 350 of the relay 348 is reset byhand..' The alarm 349 thus indicates the cause of the alarm temporarily,and the alarm 352' will continue to operate until the watchman isattracted by the signal and stops it. It will-be understood that ifdesired, only one ofthe two alarms need be used.

If the variation'of the capacity of an antenna takes place so slowlythat no signal should be given, for instance on account of atmosphericchanges, the-amplifier current changes so gradually that the regulatoris operative to compensate for the, variation of the capacity or theplatecurrent respectively, and the signaling devices are not thenoperated. If, on the other hand, the capacity variationlof the antennatakes place so quickly that a signaljshould be given, for

instance in consequence of theapproach of a burglar toward one of theantenna disposed along a wall, around a window or door or otherwise, theamplifiercurrent will use rapidly and the alarm deviceswill be operatedsince the regulator will not then beable to compensate for the capacityvariation.

it is necessary only to interchange the contacts 339 and 338 ofthe relay334.

If it is desired to provide an arrangement such that upon approach of a'body to the antenna, resonance effect between the anten- By providing afourth contact strip on the distributor, annunciators may also beoperated, which will show at a glance at what particular place thedisturbance has taken place.

It is obvious that the systems of connections described and illustratedare but few of the arrangements possible for carrying out my invention.'will be able to modify the different systems according to variousrequirements and con- Thoseskillecl in the art ditions without departingfrom the spirit and scope of the invention, and the applicability oftlie'invention to Various purposes as also the manner of arranging andconcealin'g the antenna leads will be readily appreciated. I

Therefore, it is not intended that the invention shall be limited by theappended claims to the specific constructions, arrangements andcombinations asherein described and disclosed in the drawings.

I claim: I

1. A signaling apparatus comprising a circuit including a controlconductor, an oscil lating system connected with said circuit to induceoscillations therein, a regulator compensating for variations infrequencies occurring from normal influences upon the circuit, andindicating means responsive only to uncompensated rates of variation ofthe resonant frequency of said circuit occasioned by abnormal influencesthereon.

2. A signaling apparatus comprising a cii cuit including a controlconductor, an oscillating system connected, with said circuit to induceoscillations therein, a regulator embodying a thermal element traversedby current from said oscillating system for compensating for variationsin frequencies 00- curring from normal influences upon the circuit, andindicating means responsive only to uncompensated rates of variation ofthe resonant frequency of said circuit occasioned by abnormal influencesthereon.

3. A signaling apparatus comprising a cirtermined rate for causing saidcircuit to be compensating means operating at a prede-' maintained at aconstant frequency after each change dependent upon the variation causedin the system, and indicating means.

operated by a change-in the system causing the frequency thereof to varyat an abnormal h rate.

"4. A signaling apparatusi comprising a circuit including a controlconductor, an oscillating system connected with said circuit to induceoscillationsthereiin'ia regulator.

compensating for variations in frequencies occurring from normalinfluences upon the circuit, and indicating means responsive only saidcircuit occurring at a rate above a precillating system connected with"said circuit} determined value.-

5. A 'signa l1ng apparatus comprising a c rcuit including a controlconductor, an os-j the thermal expansion of said liquid and means fortransmitting the Variations of capacity to said system to compensate forI normal variations in the resonant frequency fof said circuit. 7

10. A- signaling apparatus Comprising a to induce oscillations therein,"indicating plurality of local stations, each having a cirmeans connectedto said circuit, a heating coil in said system, and means including saidheating coil for varying "the electrical'coiistants of the scillatingsystem to compensate for variations of the resonant frequency of saidcircuit where the rate is different from the rate to be indicated. 1

6. A signaling apparatus comprising a circuit-including'a controlconductor, an oscillating system connected with said circuit to induceoscillations therein, indicating means connected to said circuit, aheating coil connected to saidsysteni, and means including said heatingcoil" for varying the capacity of a portion of the oscillating system tocompensate for normal variations in.

the resonant frequency of said circuit.

'7. A signaling apparatus comprising a circuit including a controlconductor, an oscillating system connected with said circuit to induceoscillations therein, indicating means associated with said circuit, aheating coil. connected to said system so that its current varies inaccordance .with changes in frequency of the system, a condenser, andmeans including an expansible liquid as one element thereof associatedwith the heating coil for'varying the capacity of a portion of theoscillating system to compensate for norfma-l variations in the resonantfrequency of said circuit.

8. Asignaling. apparatus comprising a circuitincluding a controlconductor, an oscillating sys tem connected with said circuit to induceoscillations therein, indicating means associated with said circuit, aheating -coil connected tosaid system so that its curbodying a 'vesselcontaining a liquid of high,

thermal, expansion coeflicient associated said heating coil and meansincluding said condenser-for. varving the capacity of a portion .of theoscillating system to compensate for normal .varia'tionsin theresonant,

qu y Of Said circuit. 7 l I 9, A signaling apparatus comprising a c1rcuit. includinga'control conductor. an oscillating system connected withsaid circuit to induce oscillations therein, a heating coil connected tosaid. system so that its current va ries in accordance with changes infrequency of tlie system, 'avesse'l containinga l quid of high 'thei' lijal expansion coefficient in heatcoiiducingf relation to said coil. ashunt '1 around saidheating' coilclosed bLFZtld liquid at a hightemperature, a condenser connected 3' with said vessel to be variedincapacity by cuit including a control conductor, said circuits havingdifferent resonant frequencies, a central station to which all of saidlocal stations are connected, an oscillator system and a signal at saidcentral station, means compensating for variations of frequencyoccurring below a predetermined rate so that the detecting means willnot be affected thereby, and signal indicating means operable by saiddetecting means.

12 A signaling apparatus comprising a circuit including a conductorextending relatively to an area to be protected, means including anoscillator for detecting abnormal rates of variation in the resonantfrequency of said circuit, means including a thermalresponsive elementconnected to the oscillator for compensating for variations of frequencyoccurring below a predetermined rate so that the detecting means willnot. be affected thereby, and a signal operable by said detecting means.

13. A signaling apparatus vcomprising a circuit including a conductorextending relatively to an area to be protected, means including anelectrical oscillator for detecting abnormal rates of variation in theresonant frequency of said circuit. means for compensating forvariations of frequency occurring below a predetermined rateso that thedetecting means will-not be affected thereby, said compensating meanseiiribodying a retarded controlling device for varying the frequency ofoscillation of said oscillator,

rate to counteract the effects of natural disturbances and operating asignal when the variation in frequency occurs above said predeterminedrate.

15.. The herein described method of operatnant frequency of-saidcircuit, means for' too ' of said vibrations upon the approach of anobject thereto, to produce a signal upon such change and restoring thesystem to normal at a definite rate whereby the signal will be operatedonly upon disturbances occurring above a predetermined rate.

. 16. The method of operating a continuously operative signaling systemembodying an oscillator which is subject to relatively slow naturaldisturbances characterized by gradually restoring said oscillator to itsnormal frequency upon any departure of the same from the normalfrequency whereby the signaling system is not affected by such naturaldisturbances and operating a signal upon a predetermined rapid deviationfrom the normal frequency.

17. The method of operating a signal in a signaling system embodying anoscillator characterized by generating oscillations in the system,continuously and gradually compensating the system for changes in thefrequency of the oscillations resulting from inherent or natural causesand actuating a signal upon a sudden relatively large change in thefrequency of the oscillations.

18. A continuously operative alarm system comprising an alarm, a controlconductor, an electrical oscillator, means including the conductor forcontrolling the oscillatory current from the oscillator, means formaintaining the oscillator at normal frequency despite the effects ofatmospheric disturbances and the like and means for operating the alarmupon an abnormal change in frequency of the oscillator.

19. A signaling apparatus comprising a plurality of local stations, eachhaving a circuit including a control conductor, said circuits havingdifferent resonant frequencies, a central station to which all of saidlocal stations are connected, an oscillating system and a signal at thecentral station, means for consecutively tuning said oscillating systemto the normal frequency of each of the tuned circuits at thelocalstations and means for operating said signal upon a relatively largechange in the resonant frequency of any of the tuned circuits at thelocal stations.

20. The method of operating a continuously operative signaling systemembodying an oscillator which is subject to relatively. slow naturaldisturbances characterized by gradually restoring said oscillator to itsnormal frequency upon any departure of the same from the normalfrequency whereby the signaling system is not affected by such naturaldisturbances and-operating a signal upon a relatively rapid change offrequency of the oscillator.

-21. The method of operating a signal in a signaling system embodying anoscillator characterized by generating oscillations in the system,continuously and gradually compensating the system for changes in thefrequency of the oscillations resulting from inherent or natural causesand actuating a signal upon a sudden relatively large change in thefrequency of the oscillations.

22. A continuously operative alarm system comprising an alarm, a controlconductor, an electrical oscillator, means including the conductor forcontrolling the oscillatory current from the oscillator, means formaintaining the oscillator at normal frequency despite the effects ofatmospheric disturbances and the like and means for operating the alarmupon an abnormal change in frequency of the oscillator.

23. A signaling apparatus comprising a plurality of local stations, eachhaving a circuit including a control conductor, said circuits havingdifferent resonant frequencies, a central station to which all of saidlocal stations are connected, an oscillating system and a..signal at thecentral station, means for consecutively tuning said oscillatting systemto the normal frequency of each of the tunedcircuits at the localstations and means for operating said signal upon a relatively largechange in the resonant frequency of any of the tuned circuits at thelocal stations. 7

In testimony whereof, I have signed my name to this specification.

LEO sssncmwnscn Tutmsuifi.

